1. Field
Example embodiments relate to a surface electron emission device array, for example, to a TFT inspection system for inspecting a TFT array using a surface electron emission device array, which may be used to more accurately inspect unit TFTs of the TFT array by providing the surface electron emission device array designed to correspond to the TFT array and which may reduce manufacturing costs, prevent the surface of pixel electrodes from being damaged, and/or reduce the installation cost of higher vacuum equipment.
2. Description of Related Art
As information and communication technologies rapidly progress, technologies related to image display devices are also rapidly progressing. Cathode ray tubes (CRTs) have been widely used as display devices. However, CRTs may be heavy and bulky and may dissipate too much power. Thus, there may be a limit to the extent to which CRTs may be used as modern image display devices. To replace CRTs, new concept image display devices, for example thin film transistor liquid crystal displays (TFT LCD), organic light emission displays (OLED), plasma display panels (PDP), and projection televisions, have been developed.
A TFT LCD module may include three units, for example, a liquid crystal panel, a driver circuit, and a backlight. The liquid crystal panel may include two glass substrates and a liquid crystal layer interposed between the two glass substrates, and the driver circuit may include driver large scale integration (LSI) and various circuits that may be mounted on a printed circuit board (PCB) to drive the liquid crystal panel.
FIG. 1 is a schematic view of a related art TFT LCD. Referring to FIG. 1, a related art TFT LCD may include a pixel array 31 having a plurality of unit pixels 34, a gate scan unit 32 driving the pixel array 31, and a data input unit 33. The gate scan unit 32 and the data input unit 33 may be connected to TFTs (not shown) of the respective unit pixels 34 through gate lines 32a and source lines 33a. On each of the unit pixels 34, pixel electrodes may be formed of indium tin oxide (ITO), for example, a transparent material having relatively high light transmittance. Because this TFT LCD may be well known, its detailed description will be omitted.
Inspection of a TFT LCD may be required to check for defects created during manufacture thereof. Various kinds of TFT-LCD inspection methods have been proposed.
One method is to use a modulator and a camera. For example, the modulator and the camera may be located on a TFT array substrate, and the TFT array substrate may be inspected according to brightness of an image observed through the camera. This method may be useful to inspect a small region of the TFT LCD, but it may be difficult to inspect the overall surface of the TFT LCD. Also, the modulator may have to be replaced if the modulator comes in contact with the TFT LCD substrate.
Another method may be to use an electron-gun type electron emission device. For example, the TFT array substrate may be inspected by measuring a current that may be output from the TFT array substrate when electrons are applied thereto. However, because electrons may have to be accelerated using a higher voltage, the TFT array itself may be damaged. Also, because this method may be performed in a relatively high vacuum (for example 10−7 to 10−8 Torr), manufacturing costs of large-sized vacuum equipment may be higher.